True love but she loves other

I am in love with a girl for two years.i have been in hostel for past two and half year.she used to be my friend from school days.very near to my home.their family believes me as a good.we are just 21.i am loving very truly.so i came home and told her how i feel.she said she and other loves in her class.i was broken.i told her i will not give up.we as usual talk,chat etc.what should i do?i am confident in future.any idea that i get her.i cant live without her.girls love generally changes.so i still believe.what should i do,?